The normal ear produces earwax which is conveyed outwards in the direction of the outer auditory canal by a ciliary system. The presence of a hearing aid in the outer ear can irritate the ear so that the production of wax increases. In connection with the insertion of the hearing aid in the auditory canal, it can happen that wax is pressed into the hearing aid's sound conduction opening, and in certain cases completely into the sound transducer, which is hereby ruined and must be changed. The sound transducer can also be ruined in attempts to clean the sound conduction opening. This phenomenon is a great problem for the propagation of this otherwise very attractive type of hearing aid.
The problem of wax has hitherto been solved in many different ways. Some solutions are based on a special shaping of the tip of the hearing aids, whereby the wax collects in places where it causes no immediate damage and is relatively easy to remove. Other solutions are based on replaceable or cleanable devices called wax filters which intercept the wax.
With the known embodiments, the replacement of the wax filter is a difficult operation. As example can be mentioned two commercially-available systems. The one system has a circular filter cap with internal thread and with a diameter of 3.7 mm and a height of 1.5 mm. In the filter itself there are a number of small sound holes plus two slightly larger holes. An accompanying tool for replacement is in the form of a rod with two studs in the one end. These studs fit into the two larger holes in the filter. When renewing the filter, the studs on the replacement tool are engaged in the corresponding holes in the filter cap, after which the filter cap can be screwed off. The used filter is removed from the tool, and a new filter is mounted on the tool's studs, after which it is screwed on to the hearing aid's threaded stub. Another known system uses rectangular plastic filters which are pressed down in a stub at the sound conduction opening of the hearing aid. These filters are 3.times.1.times.1.2 mm. The one side of the filter is provided with a small hole of 1.times.0.5 mm, and along the edges of the filter there is a collar which prevents the filter from being pressed too far into the hearing aid. A bar-shaped tool has a small stud in the one end and a small metal spade in the other end. The spade-shaped end is used to twist a blocked filter out of the hearing aid, and the stud is used to hold a new filter by means of the small hole in the filter edge while the filter is mounted on the hearing aid and pressed into place.
From German presentation document no. 2,258,118 and from U.S. Pat. No. 3,414,685, protection elements for hearing aids of the kind mentioned are known in the form of wax filters. In the patent documents, no guidance is provided with regard to how the filters are exchanged, presumably because this must always be carried out in a workshop for reasons of the filter's very small dimensions.
From U.S. Pat. No. 4,444,677 is known a filter element which can be introduced into the sound conduction opening on a hearing aid, and secured by means of an elastic ear plug which surrounds and is snapped on to an extension of the hearing aid housing itself. The patent document contains no guidance in the exchanging of the filter.
As will be apparent, all of the known methods are characterized by parts with very small dimensions, the handling of which places great demands on both the eyesight and motory abilities. Moreover, the users of hearing aids are frequently elderly people whose eyesight and powers of manipulation do not allow them to handle such small parts. Therefore, the users of hearing aids most often find it necessary to employ the services of a special workshop in order to get a filter replaced.
The object of the invention is to present a protection element of the kind mentioned which is very easy to mount on a hearing aid, and which provides the user with the possibility of being able to renew the filter element without having to resort to a specialist or another helper, if the user has reduced eyesight or poor motory abilities, or is suffering from both ailments.
This is achieved by designing the protection element in accordance with the invention. The protection element consists of a sound conduction tube which is firmly mounted in the hearing aid's sound conduction opening, and a filter element arranged to be mounted on the sound conduction tube by a snap connection between the filter element and the tube. The mounting is effected simply by bringing the filter element and the hearing aid together, preferably by pressing the hearing aid (which is much larger than the filter) against the filter element. The snap connection is designed in such a way that the filter element can be snapped both on and off.
By configuring the protection element according to the invention, the snapping action is effected in a manner which is perceptible, so that the user is directly able to feel in the fingers when the filter element is snapped correctly on the sound conduction tube, in that the snapping-on takes place with a slight click which can be felt with the fingers.
By configuring the protection element according to the invention, one can ensure that neither the filter element nor the sound conduction tube get damaged, even though the mounting of the filter element is effected with a relatively hard pressure. Moreover, the special configuration of the filter edge and the sound conduction tube results in a free edge arising on the filter element. This edge can serve as a surface of engagement for a tool for the removal of the filter element. Furthermore, this configuration results in the tool for the removal of the filter element being able to be very simple in design, cf. the tool discussed later. Moreover, this free edge with the engagement surface turns in towards the hearing aid itself, and thus does not inconvenience the user in any way whatsoever.
By configuring the protection element according to the invention, a relatively inexpensive and uncomplicated filter is achieved, said filter having proved to function in an excellent manner and preventing any ingress of earwax or dirt in the sound conduction opening, without any blocking of the sound conduction opening acoustically. It is very advantageous that the filter element can be produced for a low price, hereby enabling the hearing aid users to change the filter element frequently, so that a blockage capable of reducing the function of the hearing aid is avoided. Moreover, the configuration results in the filter element being slightly springy, which enables it to be designed with relatively tight fitting against the sound conduction tube, without this having any negative influence on the exchanging of the filter element. In addition, the configuration enables the outer side, i.e. that side of the filter element which faces in towards the user's ear drum, to be provided with rounded and completely smooth surfaces, so that the filter element is of no inconvenience whatsoever for the user.
By configuring the protection element according to the invention, the necessity is avoided of having to make precise and accurate contact when the hearing aid and the filter element are brought together during the mounting of a new filter element, in that the parts are shaped in such a way that they are guided into place for the snapping together, which is a very great advantage when the users themselves need to mount a new filter element on the hearing aid.
By configuring the protection element according to the invention, the possibility is afforded of providing it with smaller diameters, i.e. the whole construction can be of a slimmer form, and can thus be better used by persons with narrow auditory channels.
The invention also relates to a tool for use in the removal of a filter element from a hearing aid, in that said tool is arranged for use by the users of the hearing aids themselves. The tool must be designed in such a manner that there is no way in which it can be used incorrectly, and such that it cannot damage the hearing aid in any way, regardless of how the user applies the tool. This is achieved by designing the tool according to the invention. The tool consists simply of a plate, preferably of plastic, and with an opening of a certain clearance or diameter. The hearing aid is brought with the sound conduction opening against the opening in the tool, against which it is firmly pressed. The area on the tool is slightly funnel-shaped towards the opening, so that the hearing aid's sound conduction opening with the filter element is led towards said opening. When the hearing aid is again drawn free of the opening, the filter element is removed from the hearing aid. Also here the user will be able to perceive a slight click, which indicates that the filter has been removed. If one is in doubt, the operation may merely be repeated, in that repeated attempts will damage neither the hearing aid nor the sound conduction tube.
It can be an adavantage for the tool to be in the form of a dispenser. By this is achieved that the filter sits firmly in the dispenser until it is secured correctly on the sound conduction tube. When it is sitting correctly and firmly on the sound conduction tube, and one thereafter removes the hearing aid from the dispenser, the filter element is released along the break-lines and the hearing aid is again ready for use. Furthermore, in this way the tool is both a tool for the removal of the used filters, and a tool for assisting in the mounting of new filters, while at the same time it contains a closed chamber in which the used filters are collected, thus preventing them from being inadvertently reused, and avoiding inconveniences as a consequence hereof.
The tool according to the invention can be configured, whereby one always has a clear view of how many new filters are remaining in the dispenser, in that this can be observed directly through the transparent cover. The transparent, turnable cover has a delivery opening which can be turned to stand over a new filter and help the user, so that he can more easily guide the hearing aid down against the new filter when this is required to be mounted. In this configuration, the tool itself can constitute sales packing for new filters, thus rendering further packing unnecessary.